Basic find in terminal functionality was added in #15198. Here are some of the improvements we can make

• Highlight all instances of term in current viewport Moved to Terminal Find: Highlight all instances of term in current viewport and don't manipulate selection #134790
• Use a different selection type so that regular selection isn't hijacked, plus a color with a higher contrast can be used. Moved to Terminal Find: Highlight all instances of term in current viewport and don't manipulate selection #134790
• Find multiple instances on the same line
• Find terms that are wrapped across 2 lines
• Options: regex, case sensitivity, match word
• Add "No results" label, need to think about what to show in the gap when there are results. We probably shouldn't be searching the entire buffer when we don't have to for performance reasons. Moved to Terminal Find: Show result count #134791
• Add animation to terminal find widget just like it does on editor

Upstream improve find API issue: xtermjs/xterm.js#705

/cc @rebornix